A rapid and simple method for detecting Salmonellae in faeces was developed. It was based on the motility of Salmonellae through a semi-solid medium in a U-tube. The migration of other intestinal bacteria was retarded by means of a magnesium salt concentration. 474 stool specimens were examined for Salmonellae in parallel with the usual isolation method. A total of 39 Salmonella strains were isolated, 37 (94.9%) by means of the selective migration procedure, 26 (66.7%) when the routine method was applied. Two strains of patients in chemo-therapy were missed by the rapid method, which was moreover inefficient in detecting S. typhi, due to its slow motility. However, the rapid method is recommended in addition to conventional mediums in screening of carriers for its higher frequency of positive isolations compared with multistep procedure (+27.3%).